It is the 1960 Holiday House Model "X" (later named The Geographic). Those lines are so awesome. That big wrap around front window. Wow, this thing is neat.
Bardy Azadmard put together a nice site called www.1960prototype.com showing his trailer and some of the history behind it. Some restro pictures and quite a few ads are also on the site. Man I wish I could get my hands on one of these (if they had made more then one).